Carbon dioxide purity

Supporting Carbon Capture Utilisation and Storage

Carbon dioxide purity is an important consideration for Carbon Capture Utilisation and Storage (CCUS) processes as impurities can damage equipment/pipelines, reduce storage capacity and affect operational efficiencies. The purity of carbon dioxide must often be declared before it can be provided for storage or use (for instance for food/beverage). The purity of the carbon dioxide will vary depending on the source (such as steam methane reforming, biogas reforming, direct air capture or industrial emissions).

Whilst currently there is no fixed purity specification that CCUS industry can follow for carbon dioxide transport and storage, NPL have developed a guidance specification that has been used to develop new traceable calibration gases and purity analysis methods. These include a wide range of impurities:

NPL have supported several industries with carbon dioxide quality assurance through the following process: 

1. Risk assessment: What is the probability of occurence and severity for impurities?
2. Analysis strategy: What offline and online analytical methods are required?
3. Sampling: Where should sampling be performed for gas and particulates?
4. Purity results: NPL report confirming purity of final CO₂ product 

NPL provide the following to support CCUS industry:

• Calibration gas standards / Primary Reference Materials
• High pressure sampling
• Carbon dioxide purity analysis
• Proficiency testing